How Old Is Michael Phelps? Age Might Give US Swimmer New Challenges At 2016 Rio Olympics

American merman Michael Phelps is all about breaking records, like how he’s the first U.S. male to compete in four Summer Olympics, but this year might not be as easy for him to make world history. At 31 years old, Phelps is already “old” in terms of Olympic swimmers.

The average age of swimmers at the 2016 Rio Games is 22, the Washington Post reported Monday. After Phelps, the next-oldest swimmer is 29. Generally, a swimmer's time increases as he or she ages.

One thing that has already changed for Phelps is his diet. Back at the 2008 Beijing Olympics, Phelps shocked the internet when revealed he ate a whopping 12,000 calories a day. He would consume an entire pizza, a pound of pasta and a slew of energy drinks for dinner, the Washington Post wrote at the time. He has since changed his nutrition, opting for healthier options.

“I am eating just to maintain a weight, trying to stay between 200 and 205 pounds,” Phelps told the Associated Press in March. “I think that's kind of my ideal fighting weight. Every now and then I take what I want, but I don't go too overboard on sweets or inappropriate fuel.”

Money certainly isn’t a motivating factor. Not only has Phelps already achieved fame, he’s acquired wealth, too. He has a net worth of $55 million, according to Celebrity Net Worth. He finds himself in the company of professional athletes like tennis star Serena Williams and NBA player Carmelo Anthony. Phelps makes a majority of his money through endorsements. For reference, teammate Ryan Lochte is worth an estimated $6 million.

But, as nearly everyone already knows, Phelps isn’t your average athlete. He has an impressive wingspan, a foot size of 14 feet and is double-jointed. Possible physiological advantage aside, Phelps has continued to essentially maintain his impressive speed. At the 2008 Summer Games in Beijing, when he was 23, he clocked in at 50.6 seconds in the 100-meter butterfly. At the 2016 U.S. trials, he locked in at 51 seconds, which is only fourth-tenths of a second behind.